Research line leader: Guido Dolmans (Imec-nl)
There are a number of reasons for using energy harvesting within IoT devices, e.g., because it is difficult to reach devices for maintenance, wires are too costly because of the sheer number of devices, or because of environmental issues (Li-ion batteries are very toxic: some airlines refuse to transport IoT devices that contain Li-Ion batteries). Drawbacks of scavenging include: (i) each solution is dependent on the availability of harvestable energy sources, (ii) the upfront cost may be higher, and (iii) technology is less mature.
Energy can be harvested in many ways. The most optimal way depends on a number of factors, e.g., the environment an IoT device is located in, size and cost constraints, etc. Moreover, the amount of energy that can be harvested over time is usually not constant. For example, the kinetic energy from a moving train depends on the speed of the train, and is zero when the train has stopped. Therefore energy storage, e.g., with super capacitors, is needed to overcome periods of no or little harvesting activity. As can be observed from Figure 3, the amount of harvested power differs considerably between various sources. To substantially improve harvesting efficiency, R1 addresses the following scientific challenges:
- Intelligent and more reliable energy harvesting from multiple sources in one device.
- Harvest more energy than currently possible with new materials, with thermal harvesters as a promising solution.
- Efficient DC/DC conversion suitable for non-resonant sources with maximum power tracking for adaptation to dynamic impedance characteristics of the harvester.